There are three main ways to use direct solar energy:
Commercial photovoltaic cells deliver, as electricity, approximately 15% of the solar energy that hits them. Technical improvements are steadily increasing the efficiency and reducing the cost.
Technically simple solar heating panels can deliver, as useable heat, about 80% of the solar energy that hits them. Water, sometimes mixed with anti-freeze, is the usual medium for transferring the heat.
Anyone who has used a clothes line will recognize a good drying day as one with a breeze and low relative humidity. It takes just a small temperature increase to cut the relative humidity of air in half, making all but rainy days good drying days. The required temperature increase is easily accomplished for high volumes of air with technically simple solar collectors.